Technical Field
The disclosure concerns a gas distribution plate for a plasma reactor.
Background Discussion
A plasma reactor can employ a gas diffusion shower head to inject process gas over a workpiece, such as a semiconductor wafer. Typically, a plasma source power applicator, such as a microwave radiator, an RF inductive antenna or an electrode, is placed at the reactor chamber ceiling, in which case it is blocked by the gas diffusion showerhead. One problem is that such a shower head is typically formed of metal, which absorbs power radiated by the power applicator. A further problem is that heat generated within the plasma processing region below the gas diffusion showerhead tends to flow back (upwardly) through the gas diffusion showerhead to the power applicator. This can compromise the integrity of the system. Yet another problem is that the power applicator radiates power into the gas diffusion shower head, causing the process gas within the gas diffusion shower head to arc or breakdown into a plasma, which can divert power from the process region and/or damage the gas diffusion shower head.